1. Field of the Invention
The present invention relates to a light scanning device for applying a scanning light beam to a scanned medium to record image information on or read image information from the scanned medium by scanning the scanned medium with the scanning light beam.
2. Description of the Related Art
There are known light scanning devices in which a light beam emitted by a light beam generator is applied to scan a scanned medium in a main scanning direction by a scanning optical system including a light beam deflector, a scanning lens, etc. Such light scanning devices are widely used in recording apparatus which record a desired image on a medium with a scanning light beam and reading apparatus which photoelectrically read a recorded image from a medium.
The light beam deflector in such a light scanning device comprises a resonant light deflector, a rotating polygonal mirror, a galvanometer mirror, or the like. The light beam deflector has a reflecting surface or surfaces which tend to be unduly slanted, causing an error often known as a "facet error", due to manufacturing errors, attachment errors, or the like. If the reflecting surface or surfaces are unduly slanted, then a scanning line produced on the scanned medium when the scanned medium is scanned in the main scanning direction by the light beam is bowed, leaned, and positionally displaced (offset) in an auxiliary scanning direction which is normal to the main scanning direction.
It has been proposed to correct the path of a scanning beam as disclosed in Japanese laid-open patent publication No. 2-64521. According to the disclosed correcting process, the amounts of bow and lean of the scanning line on the scanned medium are measured, then the light beam deflector is tilted through a corrective angle that has been determined based on the measured amounts of bow and lean, and a reflecting mirror disposed between the scanning lens and the scanned medium is tilted if necessary for thereby correcting the scanning line for its offset in the auxiliary scanning direction.
With the above conventional correcting process, after the measured amounts of bow and lean have been compensated for with respect to the light beam deflector, the reflecting mirror is adjusted to correct for the offset of the scanning line. Therefore, if the light beam deflector is to be replaced with a new light beam deflector, then it is necessary to make adjustments for the new light beam deflector, and make adjustments for the reflecting mirror to match the new light beam deflector. Consequently, the overall adjustment procedure required by a light beam deflector replacement is considerably tedious and time-consuming.